| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a filter medium for an air filter, for which safety and economical efficiency are compatibly achieved by substantially improving the catching performance of submicron particles, such as diesel exhaust particles, highly affecting the health of crew while achieving a dust collecting service life, that is a dust holding amount, longer than before, in the air filter for an automobile cabin. <P>SOLUTION: As for the filter medium for the air filter, in a laminated nonwoven fabric including at least two layers of an electret nonwoven fabric arranged so as to reduce a pore size stepwise, the average pore diameter of the upper layer electret nonwoven fabric is in the range of 50-150μm, the average pore diameter of the lowest layer electret nonwoven fabric is in the range of 5-50μm, respectively, and the average pore diameter of the upper layer side electret nonwoven fabric is 2-10 times of the average pore diameter of the lower layer side nonwoven fabric. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
